Tesla flicks the switch on Powerwall sales

December 9, 2015 (Source: The Australian) — Australians gearing to add battery-stored solar energy to grid power can buy Elon Musk’s long-awaited Tesla Powerwall system from today. You’ll pay $15000 or more for a full system.

Tesla is selling two Powerwall models: a 7 kWh unit with a daily cycle designed for home use, and a 10 kWh battery that stores power for a week, for backup use.

This won’t be a case of the renewable energy economy versus conventional grid power, with energy retail giant Origin announcing it has climbed aboard the Musk wagon. It will offer Powerwalls to many of its 4.2 millions grid customers nationally. Already it has more than 400,000 solar customers.

In Australia, Tesla through its retail partners will sell installed solutions rather than stand-alone Powerwalls. Origin will sell complete home energy solution that includes Trina solar panels and a SolarEdge inverter from $16,500. The inverter converts DC from the panels to AC for household use.

Another partner, Sydney-based Natural Solar, which installs solar panels for domestic and commercial use, today also is announcing full installation packages and ballpark pricing.

Powerwalls are large lithium-ion batteries that store the energy from solar panels for later use. In addition, users can store off-peak power from the grid at night and consume it by day.

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Origin said installations would begin in February. “Tesla Energy has quickly established itself as a global leader in battery storage, so we are delighted to be collaborating on Origin’s first solar and battery offering,” said chief executive officer energy markets, Frank Calabria.

Natural Solar managing director Chris Williams said his company would offer a full solution of 20 x 250 watt solar panels, an inverter and Powerwall installed for about $15,000. Adding a Powerwall to an existing solar installation would cost about $9500. A Powerwall and inverter without installation about $1000 to $1200 less.

Simply Energy, a retailer in Victoria, New South Wales and Queensland with 550,000 accounts will also sell Tesla Powerwall packages from today.

Australians have been waiting for months to find out the cost of a Powerwall system. They can be bought wholesale for $US3000 and $US3500 in the US.

Mr Williams said there had been battery solutions before, but they had cost $40,000 to $70,000 and typically were adopted by users with no grid power access. He pointed to the dramatic drop in price of polysilicon used in solar panels and lithium-ion batteries which showed the technology was getting much cheaper. Costs were dropping 8-10 per cent each year.

With pricing now revealed, consumers will be doing their maths on a Powerwall solution’s financial viability, and its ability to deliver sufficient power. The battery holds 7 kWh. Laptops typically use 0.05 kWh/hr, a flat screen TV 0.1 kWh/hr and a fridge 1.6 kWh/day. A clothes dryer however uses 3.3 kWh each time and a large air conditioner, say, 5 kWh/hr when switched on, maybe 2 kWh/hr when the room is cool.

But providers see Powerwall as supplementing rather than replacing grid power. At day, a solar system outputting 5 kWh would power a home while it slowly charged Powerwall. Battery power could be used in the evening. At night, the battery could be charged again, this time from the grid at an off peak-rate for morning use.

Mr Williams said a battery output of 3.3 kWh at 240 volts would deliver a current of 13.75 ampere. That would be enough to support to run lights, TVs and computers concurrently.

A reverse-cycle air conditioner running at 5 kWh per hour may initially drain power when it was turned on but power consumption would drop to 1-2.5 kWh/hr after it stabilised the temperature.

He cited the example of solar panels at 6.5kWh sending 5 kWh to an inverter for home use and 1.5 kWh charging the Powerwall. In that circumstance there would be enough power to drive the air conditioner straight from the solar panels.